Former White House aide picked as agriculture secretary

US President-elect Donald Trump has chosen Brooke Rollins, president of the America First Policy Institute, to be agriculture secretary.

"As our next Secretary of Agriculture, Brooke will spearhead the effort to protect American Farmers, who are truly the backbone of our Country," Trump said in a statement on Saturday.

If confirmed by the Senate, Rollins would lead a 100,000-person agency with offices in every county in the country, whose remit includes farm and nutrition programs, forestry, home and farm lending, food safety, rural development, agricultural research, trade and more. It had a budget of $US437.2 billion ($A672.6 billion) in 2024.

The nominee's agenda would carry implications for American diets and wallets, both urban and rural. Department of Agriculture officials and staff negotiate trade deals, guide dietary recommendations, inspect meat, fight wildfires and support rural broadband, among other activities.

"Brooke's commitment to support the American Farmer, defence of American Food Self-Sufficiency, and the restoration of Agriculture-dependent American Small Towns is second to none," Trump said.

The America First Policy Institute is a right-leaning think tank whose personnel have worked closely with Trump's campaign to help shape policy for his incoming administration. She chaired the Domestic Policy Council during Trump's first term.

As agriculture secretary, Rollins would advise the administration on how and whether to implement clean fuel tax credits for biofuels at a time when the sector is hoping to grow through the production of sustainable aviation fuel.

The nominee would also guide next year's renegotiation of the U.S.-Mexico-Canada trade deal, in the shadow of disputes over Mexico's attempt to bar imports of genetically modified corn and Canada's dairy import quotas.

Trump has said he again plans to institute sweeping tariffs that are likely to affect the farm sector.